package com.kmzx.gen.signs.utils;

import java.io.Serializable;
import java.net.InetAddress;
import java.text.SimpleDateFormat;
import java.util.Date;

public class UUIDGenerator implements Serializable {

    private static final long serialVersionUID = 2657666156041750492L;

    private static final int IP;

    private static int toInt(byte[] bytes) {
        int result = 0;
        for (int i = 0; i < 4; i++) {
            result = (result << 8) - Byte.MIN_VALUE + (int) bytes[i];
        }
        return result;
    }

    static {
        int ipadd;
        try {
            ipadd = toInt(InetAddress.getLocalHost().getAddress());
        } catch (Exception e) {
            ipadd = 0;
        }
        IP = ipadd;
    }

    private static short counter = (short) 0;
    private static final int JVM = (int) (System.currentTimeMillis() >>> 8);

    public UUIDGenerator() {
    }

    /**
     * Unique across JVMs on this machine (unless they load this class in the
     * same quater second - very unlikely)
     */
    protected static int getJVM() {
        return JVM;
    }

    /**
     * Unique in a millisecond for this JVM instance (unless there are >
     * Short.MAX_VALUE instances created in a millisecond)
     */
    protected static short getCount() {
        synchronized (UUIDGenerator.class) {
            if (counter < 0)
                counter = 0;
            return counter++;
        }
    }

    /**
     * Unique in a local network
     */
    protected static int getIP() {
        return IP;
    }

    /**
     * Unique down to millisecond
     */
    protected static short getHiTime() {
        return (short) (System.currentTimeMillis() >>> 32);
    }

    protected static int getLoTime() {
        return (int) System.currentTimeMillis();
    }

    private final static String sep = "";

    protected static String format(int intval) {
        String formatted = Integer.toHexString(intval);
        StringBuffer buf = new StringBuffer("00000000");
        buf.replace(8 - formatted.length(), 8, formatted);
        return buf.toString();
    }

    protected static String format(short shortval) {
        String formatted = Integer.toHexString(shortval);
        StringBuffer buf = new StringBuffer("0000");
        buf.replace(4 - formatted.length(), 4, formatted);
        return buf.toString();
    }

    public static String generate() {
        UUID uuid = UUID.randomUUID(false);
        String s = uuid.toString(true);
        return s;
    }

    public static String generate(boolean isSafe) {
        UUID uuid = UUID.randomUUID(false);
        String s = uuid.toString(isSafe);
        return s;
    }

    public static String generator() {
        return new StringBuffer(36).append(format(getIP())).append(sep)
                .append(format(getJVM())).append(sep)
                .append(format(getHiTime())).append(sep)
                .append(format(getLoTime())).append(sep)
                .append(format(getCount())).toString();
    }

    public static String generator(int capacity, boolean defaults) {
        StringBuffer buffer = null;
        if (defaults) {
            buffer = new StringBuffer(36);
        } else {
            buffer = new StringBuffer(capacity);
        }
        return buffer.append(format(getIP())).append(sep)
                .append(format(getJVM())).append(sep)
                .append(format(getHiTime())).append(sep)
                .append(format(getLoTime())).append(sep)
                .append(format(getCount())).toString();
    }


    /**
     * 生成随机订单号
     * 总长度 32
     *
     * @return
     */
    public static String generateOrderNo(String prefix) {
        int machineId = 1;
        int hashCodeV = java.util.UUID.randomUUID().toString().hashCode();
        if (hashCodeV < 0) {
            hashCodeV = -hashCodeV;
        }
        String orderNo = machineId + String.format("%015d", hashCodeV);
        SimpleDateFormat format = new SimpleDateFormat("yyMMddHHmmss");
        orderNo = prefix + format.format(new Date()) + orderNo.substring(10, orderNo.length());
        if (orderNo.length() > 32) {
            orderNo = orderNo.substring(0, 32);
        }
        return orderNo;
    }


}
